Shock absorber



v Det?.v 10, 1940. v E w. KRUEGER 2,224,302;

1- SHOCK ABSORBER Filed March 29'; l19:59

` ATrQRNEY Patented Dec. 10, 1940 UNITED. s'rii'nizsV PATENT orifice SHOCK ABSORBEB vElmer W. Krueger, Cleveland, Ohio, assigner to The Cleveland Pneumatic Tool Company, Cleveland, Ohio, a corporation of Ohio Application March29, 1939, Serial N0. ,264,817

8 Claims. (Cl. 18S-88) This invention relates broadly to a shock absorbing device useful in the arts in general, and more particularly for use on vehicles such as automobiles or the like to prevent excessive ,movementl of the vehicle body relative to its axles.

One 'object of this invention is to produce an improved shock absorber of the direct acting hydraulic type including a pair of telescoping cylinders provided with valve controlled passagesl enabling freer telescopic movement of'the cylinders in one direction than in the other, thereby making the device particularly useful as a recoil checking mechanism.

Another object of this invention is to produce such a shock absorber with adjustable means for varying the degree of freedom of the recoil move- 'ment of the cylinders, the means being readily adjustable from the exterior of the shock absorber before installation, thus rendering the shock ab? 2 0 sorber applicable to all kinds of vehicles irrespective of the load carrying capacity thereof.

Other objects and advantages more or less ancillary to the foregoing reside in the speciilc construction and aggroupment of the elements peculiar to this structure. as will become apparent from a more complete examination oi' this specication.

In the drawing:

Fig. 1 represents a perspective view of the shock absorber connected to parts of a vehicle rwhose relative lmovements are to be cushioned. Fig. k2 is a side elevational view partly in section ofthe shock absorber shown in a fully compressed position. A

` Fig. ais e view similar tong. 2 niustraungtne Y shock absorber in a fully extended position. Fig. 41s anc'nlrged fragmentary sectional view of the shock absorber as shown in Fig. 3. I Fig.5 is a view similar to Fig. 4 of the shock absorber in the-position shown in Fig. 2.

Fig. 6 is an enlarged secti nal view taken in a plane indicated by line S--f-i in Fig. 2.

Fig. 7 is an enlarged sectional view taken in a plane indicated by line 1-1 in Fig. 2.

Referring to the drawing; the lshock absorber includes two telescoping cylinders I0 and il, the former being the outer cylinder laterally spaced from the inner cylinder to form: therebetween an annular chamber I2 closed at its upper en d by a head I3 formed with an external annular iian'ge M resting on the upper end of the outer cylinder I0 and clamped thereon by a cap il threaded on the cylinder lil. 'I'he head Il carries two longi- 1 tudinally spaced internal packing rings IC and a 5 similar external ring l1 ailoldin a iiuid tight lnated by 6i, which'reservoir extends from the 20 joint between the head and the two cylinders, while the head I3 is internally machined to fit closely on the cylinder il and act as a sliding bearing betweenV the two cylinders. t The lower or outer end or the inner cylinder 5 Il carries an insert i8 preferably welded in position as at i9, which insert extends beyond the v extreme end of the cylinder and has mounted thereon a piston 2l secured in position by a nut 2|, and is closely iltted for slidable engagement 10 with the inner wall of the cylinder lil to act as a sliding bearing between the two cylinders. This piston also carries a packing ring 22 -in iluld tight engagement with the inner wall of the cylinder I0. Between its ends, the insert i8 is provided 1l with a partition 23 having a plurality of relatively large ports 2l extending longitudinally therethrough. 'I'he interiors of the -two cylinders form a liquid reservoir or chamber generally desigclosed upper end of the inner cylinder il to the closed lower end of the outer cylinder Il, and is actually divided by the ported partition 23 to form a reservoir upper portion 62 extending from the partition 23 to the closed upper end of the 25 inner cylinder Il, and a reservoir lower portion 63 extending from-the piston 2li or its partition 23 to the closed lower end of the outer cylinder I0. The ports 24, extending through the partltion 23. afford free communication between the n y upper portion i2 of the reservoir 6I and the lower portion .6I thereof. Below this partition the in-V sertisinternailythreadedasattoreceivea plug 26 provided with aplurality of equally spaced ports 21 longitudinally extended therethrough. g

'Within one of theseports thereis slidably mounted an adiusting pin 28 formed intermediate its ends with a collar 29 on which is seated a compression spring II constantly urging the pin 2l downwardly. Thispinisretainedintheplug 2i n by two retaining washers 3l and 32, the former engageable by the collar 29 of the-pin 28, and the latter by the compression spring Il. These two washers are securedone on eachside oftheplug 2i by a rivet ll extending centrally through the a plug and made to project upwardly therefrom partway into a coimterbore ll provided withinV the partition 23. The plug 2G is normally heldagainst accidental rotation by the frictiunal engagement o! a compression spring il interposed n between the plug and the partition 2 3. Y

Extending longitudinally through the piston 2l, Y thereisapluralityofsemicircularslotsorpassages capalileot beingclosed by a plate valve. Il slidalilymountedlietweeitheendofthetuiie I I and the adjacent end of the piston 26, and normally urged into engagement with the end of the tube II by a plurality of compression springs 36 located within blind holes 39 formed in the` ment with the partition 23 by a compression spring 42, which spring is interposed between the valve 4I and the rplug 26. To prevent lateral distortion of the spring 42, there is provided a short annular sleeve 43 resting on the washer 32.

The lower or outer end of the outer cylinder I6 has rigidly secured thereon a cup-shaped terminal 44 formed with a bottom wall 45 and a hollow stem 46. Within the wall 4 5 there is provided a blind hole 41 adapted to receive the lower end portion of the pin 26 slidable within the plug 26 for the purpose which will be explained later. The upper end of the inner cylinder II is also closed by a terminal 46 rigidly secured. thereto by any suitable means and having a hollow stem 49 similar to the stem 46 of the terminal 44. Mounted within each stem of the terminals l44 and 46, there isa ball and socket joint including a ball 56'and the two sockets 5I and 62, the former resting on a plug 53, while the latter is urged toward the ball 56 by a compression spring 54. The ball 56 is formed with an integral shank 65- extending radially through the terminal, which shank carries a nut 66. Secured to the terminal 43 and to the upper end portion of the outer cylinder I6, there is a bellows boot or flexible circular casing 51 preventing a ssion of dust or other foreign matter on the inner cylinder when the shock absorber is in the extended position as shown in Fig. 3. 'Ihrough the upper terminal, there is also provided a threaded bore 66 adapted to receive a filler plug 69 and an air valve 66.

In practice, the upper terminal 46 is preferably secured-'to theframe ofthe vehicle by the shank and nut 66, while the lower terminal 44 is similarily alxed to the axle or spring of the vehicle as shown in Fig. l. Before installation, however, the shock absorber is fully compressed as shown inFig.' 2 andv liquid such as oil is poured into the reservoir 6I by removing the filler plug 69. During this process, the shock absorber is extended and again compressed several times to entirely bleed the air out of the chamber I2. When a suilicient amount of liquid is available, the shock absorber may first be lled when in fully extended position, as shown in Fig. 3, in which instance it Is subsequently fully compressed with the oil plug 69 still removed, thereby causing the liquid from the lower portion 63 of the reservoir 6I to flowinto the chamber.l2 vi'a thel pistons passages 36, and the excessive amount of liquid in the upper portion 62 of the reservoir 6I to escape i through the bore u. when tneiiquid has :ined

act as a cushion interfering with the free conif pression .strokes of the shock absorber. The distance between the shanks 55 of the ball and socket joints mounted within the terminals of the shock absorber, is calculated to cause partial compression of the shock absorber when finally installed as shown in Fig. l. In other words, when thevehicle is at rest, the piston 26 will be positioned at substantially equal distance from the ends of its possible'stroke within the cylinder I6. During operation, forces tending to move the frame of the vehicle closer to the axle thereof, or

in other words, tending to cause the compression of the shock absorber-,will effect displacement cf the liquid within the reservoir 6I from the lowerA portion 63 tothe upper portion 62 thereof `through thev ports 21 of the plug 26 and the ports 24 of the partition 23, and from the reservoirs lower portion 63 into the annular chamber I2 through the pistons passageways 36. In thisinstance, the displacement of the liquid and consequently the compression of the shock-absorberisresisted only by the atmospheric air stored Within the upper portion 62- of the reservoir 6I, thus enabling a relatively free compression stroke of the shock absorber and permitting the leaf spring of the vehicle'to absorb the ,load in the usual manner.

Subsequently, the energy stored within the leafI spring during its compression or deflection, will cause rebound or recoil movement of the vehicle frame relative to the axle, resulting in the expansion stroke of the shock absorber. In this instance, thecompression springs 36 active on the valve 31 are calculated to hold the valve 31 open relative to the pistons passageways 36 during the return flow ofthe liquid from the chamber I2 into the reservoir 6I below the piston 26, or more y particularly into the lower portion 63 of the resward displacement of the piston 26 relative to the cylinder I6 will not, exert suilicient pressure on the liquid Astored within the chamber I2 to'close the valve 31, thereby enabling the valve to remain open and allowing an unrestricted flow of the liquid from the annular chamber I2 to the lower portion 63 of the reservoir, However, when the vehicle is subjected to more pronounced shocks, the rebound movements resulting therefrom will tend to cause the expansion of the shock absorber at a greater rate of speed, and consequently subject the liquid within the-annular chamber I 2 to a. greater pressure corresponding to the rate of speed at whichthe piston 26 moves upwardly in the cylinder I 6. In this instance, the increased pressure acting on the valve 31 will overcome the combined pressure of the compression springs 36 and shift the valve into engagement with the piston 26 for opening the outer ends of the ports 46 and closing the pistons. passageways or slots 36. With the valve 31 in this position, .the liquid from the annular chamber I2 will ow through the restricted ports 46 into the counterbore 34 to exert pressure on the ring valve 4I. When the liquid pressure onthe valve 4I is,

sufficient to partly overcome the pressure of the compression spring 42, .the valve 4I will shift into more or less complete open position relative to the counterbore 34 and consequently to the restricted ing of the valve 31 is responsive to pressure conditions of the liquid within the annular chamber I 2, Ait will understood that the valve 4I by controlports 4,6. Since the more or less complete openling the liquid conveying capacity of the ports 40 also controls the degree of freedom at which the shock absorber may be expanded. which degree of freedom may be varied as hereinafter explained. With the valve 4I opened, the liquid from the counterbore 24 will flow through the plugs ports 21 into the lower portion 62 of the reservoir 6I, while some of the liquid in the reservoir 6| will also flow from the upper portion 82 into the lower portion 63 thereof via the 'ports 24 and 21.

From the foregoing description, it will be clear that the expansion of the shock absorber under favorable Vroad conditions is not affected by the displacement of the liquid in the shock absorber, thereby enabling the vehicle's springs to cushion relative movements of the vehicle frame and axle. Under more adverse road conditions, that is, when the frame has the tendency to rebound relative to the axle to an extent which would be uncomfortable to the passengers, the shock absorber will automatically check this rebound by restricting or retardng the flow of the liquid from the annular chamber I2 into the lower portion 63 of the reservoir 6i. This checking of the liquid flow and consequently checking of the rebound is primarily controlled by the pressure of the compression spring 42 active on the ring valve 4l. which pressure is adjustable as hereinafter explained. To that end, before installation of the shock absorber, the plug 26 on ,which is seated the compression spring 42 may be moved longitudinally into the insert IB by the simple relative rotation of the cylinders i0 and Il. In this instance, the pin 28 located within the blind hole 41 provided within the terminal 44 of the cylinder I0, will upon rotation of that cylinder relative to the cylinder Il, rotate the plug 26 within the screw thread bore 25 of the insert IB, thereby increasing or decreasing the compression of the spring 42. For instance, when the shock absorber is to be installed to vehicles of heavy duty, the cylinders will be rotated relative to one another for decreasing the compression of the spring 42, thereby necessitating lower pressure oi' the liquid stored within the chamber I2.to shift the valve 4I into open position relative to the counter-bore 34. Thus by varying the compression of the spring 42, it is possible to vary the liquid conveying capacity of the opening between the valve 4l and the partition 23 of the insert I8, which capacity can be controlled to regulate the riding qualitiesof the vehicle.

As previously stated, whenthe shock absorber is used as an auxiliary snubbing device between the vehicle spring and the frame. the compression of the shock absorber is restricted only by atmospheric airV trappedAn the yupper portion 82.

of the reservan 6I during the rising of the liquid level within that portion of the reservoir. However when the shock absorber is to be used as an additional spring, compressed air maybe admitted into the upper-portion 62 of the reservoir 8l through the air valve 0I until the air within that portion of the reservoir has reached a predetermined pressure, which pressure will act as a resilient medium to cushion movement of the -vehicle parts toward each other and will not aiect the recoil checking function'ofthe l'shock absorber in the manner above explained.

Although the foregoing description is necessarilyof a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it .is t0 be further understood that various rearrangements of parts and modifications of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

l. A hydraulic shock absorber comprising a pair of telescoping cylinders forming a liquid reservoir of varying volumetric capacity. liquid stored in said reservoir, an annular chamber between said cylinder closed at one end, a piston on the inner end of the inner cylinder forming the other end of said chamber, a passage through said piston enabling relatively free iiow of the liquid between said reservoir and chamber during normal expansion and compression strokes of said cylinders, a restricted port leading from said chamber into -said reservoir, a valve normally closing said port, said valve being responsive to a predetermined pressure within said chamber during the expansion strokes of said cylinders for closing said passage and opening said port, and a second valve responsive to pressure conditions within said chamber during the expansion strokes of said cylinders for controlling the liquid conveying capacity of said port..

2. A hydraulic shock absorber comprising a pair of telescoping cylinders, a duality of fluid vchambers within said cylinders having iiuid stored therein, a port and a passage enabling vdisplacement ofthe iluid between said chambers during the telescopic movement of said cylinders, a valve normally closing said port, said valve being responsive to a predetermined pressure of the fluid within one of said chambers during the expansion stroke of said cylinders for opening said port yand closing said passage, and a second valve responsive to said pressure for controlling the iluid conveying capacity of said port.

3. AA hydraulic shock absorber comprising a pair of telescoping cylinders, a duality of liquid containing chambers with said cylinders, a pair of passageways affording intercommunicatlon ofl said chambers, a valve responsive to a predetermined pressure of the liquid within one of said chambers during movement of said cylinders in one direction for closing one of said passageways and opening the other, and a second valve responsive to said pressure for controlling the liquid conveying capacity of said other passageway. 4. A hydraulic shock absorber comprising a pair of telescoping cylinders, a duality of' liquid containing chambers within said cylinders one smaller than the other, a pair of' passageways capable of affording intercommunication of said cylinders, a valve for each of said passageways, spring means operatively associated with each valve for normally maintaining one open and the other `closed relative tmtheir respective 'passageways, said valves being responsive to pressure conditions of the liquid within the smaller chamber during the expansion strokes or said cylinders one for closing its normally opened and the other for opening its normally closed passageway.

rsv

-v liquid stored therein, a piston xed to the inner end of the inner cylinder forming one end of said chamber, passages between said reservoir and chamber enabling displacement 'of the liquid.

therebetween during the telescoping movement of said cylinders, a valve for controlling at least one of said passages, a compression spring urging said valve in closed position relative to said passage, and means actuated by virtue of relative rotation of said cylinders when at the end of their stroke in one direction for varying the compression of said spring.

7. A shock absorber comprising a pair of telescoping cylinders, a reservoir within and an an- -nular chamber between said cylinders having liquid stored therein, a piston fixed to the inner end of the inner cylinder in slidable engagement with the inner wall of the outer cylinder, interconnecting means between said reservoir and chamber, valve means enabling during the reciprocatory movement of said cylinders at a predetermined rate of speed a freer flow of the liquid from said reservoir into said chamber than from said chamber into said reservoir, and means responsive to relative rotation of said cylinders for varying the degree of freedom of the liquidflow from said chamber into said reservoir.

8. A shock absorber comprising a pair of telescoping cylinders capable of relative' rotation, a piston fixed on the inner end of the inner cylinder in slidable engagement with the outer cylinder, chambers in said cylinders having liquid stored therein capable of displacement therebetween in two directions upon telescopic movement of said cylinders, means including a valve controlling said displacement in one direction, a

'seat for said valve, a spring active on said valve 2o urging it into engagement with said seat. and means responsiveto said relative rotation-for varying the force'of vsaid -spring on said valve.

Emma w. muisarm; 

